I generally think of myself as being a drinker of many different wines and a quick search of CT will show that the vast majority of wines I have bought I only get between 1 to 3 bottles (have almost 500 producers in my cellar). But on the converse, when I like a producer, I get stuck on them and they appear to dominate my cellar. My top tive account for 20% of my cellar, mostly due to verticals. Also to my surprise, while I own more Bordeaux and Burgundy than anything else, my top three producers are not from those locations (and decidedly mainstream):

Not finished entering my collection on CellarTracker but I think it's a safe bet that my top producer is Williams Selyem. Runner-ups include Ridge (mostly Lytton Springs), Merry Edwards and Loring Wine Company and Biale (mostly Zinfnadels.) I am starting to add Alysian wines (Gary Farrell's new venture) and Lioco wines (Pinot Noir and Chardonnay.) I usually buy one to three of a particular wine at a time and occasionally four to six but no full cases. A holdover from past purchase decisions are some Marquis Phillips (mostly Shiraz and Sarah's Blend.) They aren't that appealing to me now so may sit for a long time or be offered as gifts to anyone locally that wants them.